Problem: Rewrite ${((7^{-9})(3^{-5}))^{4}}$ in the form ${7^n \times 3^m}$.
Solution: ${ ((7^{-9})(3^{-5}))^{4} = (7^{(-9)(4)})(3^{(-5)(4)})} $ ${\hphantom{ ((7^{-9})(3^{-5}))^{4}} = 7^{-36} \times 3^{-20}} $